Field of the Technology
The present application relates generally to wireless communication devices which communicate with both wireless local area networks (WLANs) and cellular networks, and more particularly to the communication of cellular network information for one or more cellular networks to a mobile station through a WLAN.
Description of the Related Art
In the field of wireless local area networks (WLANs), there is an existing method of broadcasting information specific to a WLAN using binary and textual information. There is also an initiative to enable a WLAN to communicate with one or more 3rd Generation Partnership Project (3GPP) cellular networks in order to provide cellular users access to a higher bandwidth via the WLAN while still being able to access their cellular service.
WLANs were originally designed for wireless LAN connectivity; no provisions were made for cellular network communication. Traditionally, no suitable way has been provided to advertise whether “interworking” between a WLAN and cellular networks exists. Further, no suitable techniques have been established to identify which cellular networks a given WLAN may interwork with or any other information for allowing a mobile station to select cellular networks for communication.
Currently, a WLAN may broadcast a textual string, referred to as a Service Set ID (SSID), to identify itself. WLAN operators often establish their own broadcast information (i.e. an SSID) specific to their needs, including such data as branding information and/or a name for use by a smart client application. WLAN operators are reluctant to change their broadcast SSIDs to make them compatible with cellular network identifiers.
Interconnection amongst multiple networks requires that a Subscriber Identity Module (SIM) or Universal Subscriber Identity Module (U-SIM) be used to identify the subscriber. The U-SIM also contains information that identifies preferred and forbidden networks that the subscriber is allowed to use. This information is stored as a Mobile Country Code (MCC) and a Mobile Network Code (MNC) pair in the SIM or U-SIM. If a broadcast SSID has been assigned to a WLAN and the WLAN operator does not wish to change it, there is no established way that the MCC and MNC pair can be broadcasted from the WLAN to the mobile station.
There is a mechanism that allows the mobile station to probe the WLAN for other supported SSIDs. The WLAN will only respond to a probe request, however, if the WLAN supports the SSID. Therefore, a mobile station would need to probe for every known network to determine whether the WLAN supports cellular network interworking. Such a method is time-consuming, inefficient, and reduces the battery life of the mobile station. There is a resulting need for a more efficient method to provide cellular network information to a WLAN enabled mobile station.